www.pudn.com > voiceprocessingtoolbox.rar > fftAudioExample.m

% This example demos the effect of FFT approximation 
 
[y, fs]=wavread('welcome.wav'); 
x=y(2047:2126); 
x=y(2047:2326); 
n=length(x); 
F = (0:n/2)*fs/n; 
 
runNum=1; 
for i=1:runNum, 
	newX=x(1:2^(i-1):length(x)); 
	newFs=fs/(2^(i-1)); 
	X = fft(newX); 
	magX = abs(X); 
	frameSize=length(newX); 
 
	subplot(runNum,2,2*i-1); 
	plot(newX, '.-'); 
	title('x[n]'); 
	set(gca, 'xlim', [-inf inf]); 
 
	subplot(runNum,2,2*i); 
	freq = (0:frameSize/2)*newFs/frameSize; 
	magX = magX(1:length(freq)); 
	M=nan*F; 
	M(1:length(magX))=magX; 
	plot(F, M, '.-'); set(gca, 'yscale', 'log'); 
	title('DFS of x[n]') 
	axis tight; 
end